Airborne Mycotoxin Sampling and Screening Analysis

The indoor mycotoxins inhalation exposure of patients (n=25) was studied using a highvolume air sampler (60 cfm x 24 h) with a micropore-paper filter (8x11 inches). The filters were evaluated for cytotoxicity caused by mycotoxins using the MTT-cell culture bioassay and by culture identification. A subset of samples was analyzed with an enzyme-immuno assay for occurrence of macrocyclic trichothecenes produced by Stachybotrys chartarum and HPLC-DAD and GC-MS analyses for different mycotoxins. Highly toxic air samples (IC50 ≤ 31 mg/ml) were found in seven cases; moderate toxicities (IC50 > 31 to ≤ 125 mg/ml) in 14 cases, and four cases were not toxic compared to controls. The subset testing demonstrated that macrocyclic trichothecenes and other mycotoxins could become airborne. In conclusion, an inhalation risk could be confirmed (84% of cases) with the 24-hour high volume air sampling test method due to the detection of airborne cytotoxic fungal particles and specific mycotoxins, including trichothecenes produced by Stachybotrys fungi. INDEX TERMS Indoor mycotoxins, Cytotoxicity, MTT bioassay, Stachybotrys c., Inhalation risk INTRODUCTION Mycotoxins consist of a group of more than 400 chemical compounds produced by several fungal genera and species. The production of mycotoxins is dependent on the toxigenicity of the particular fungal strain, the composition of the substrate and various external factors such as water activity, pH-value, temperature, oxygen and the presence of competitive microorganisms. In indoor environments the occurrence of several fungal species and mycotoxins has been demonstrated, typically after significant water damage and with high moisture on cellulose materials. Mycotoxins produced by fungi (i.e., Stachybotrys chartarum (S.c.)) may be causal agents in non-agricultural exposures that are associated with immune suppression and central nervous system disorders. Toxic effects of mycotoxins in humans have been discussed primarily in the context of ingestion related poisoning, but to a much lesser degree related to inhalation risk. This appears to be due to prior sampling difficulties and analytical limitations. In the past indoor air microbial investigations and exposure assessments have generally relied on mycological identification using viableand non-viable methods (culture ID, fungal spore counts, bulk and air sampling), which may give qualitative or quantitative information about the presence of particular fungi, but not its particular properties (toxicity?). Laboratory chemical analyses of bulk materials from contamited homes do not necessarily reflect the true conditions in the buildings („in vivo toxicity“) and may therefore be misleading. Clinical experience shows that a variety of patients working or living in buildings * Contact author email: [email protected] Proceedings: Indoor Air 2002